The 17" will have less sidewall and also more tough inner tire construction. So it's going to ride a lot more firm. However, I've never seen anything relating to wheel diameter or load rating affecting sound levels.
My 33x12.50-15 Duratracs were very quiet for the first 5,000 miles. They were about the same as some AT tires I've used. Hankook Dynapro ATM, Cooper ATP, BFG KO are all the same noise level as the Duratrac when new. However, at 5,000 miles I did a cross-rotation and then the noise became noticeably louder. Still not MT levels...but definitely noticeable.
~Lots of modded Jeeps and a Toyota 4Runner~
My favorite quote from the press release.. sad but true: "Chrysler claims its products, especially the Jeeps, can handle all sorts of terrible conditions, churning through muddy swamps, climbing mountains, and crossing rivers. Turns out they cannot even handle a car wash."